Peripheral Hematopoietic Stem Cell Research Articles

THE ROLE OF SUBPOPULATIONS OF MOBILIZED PERIPHERAL HEMATOPOIETIC STEM CELLS IN THE RESTORATION OF HEMATOPOIESIS DURING HIGH-DOSE CHEMOTHERAPY IN CANCER PATIENTS

Mobilized peripheral hematopoietic stem cells are transplanted to cancer patients as support for high-dose chemotherapy. It is believed that the effectiveness of restoring all hematopoietic sprouts during HSC transplantation depends on the total dose of CD34+ cells. At the same time, CD34+ stem cells are a heterogeneous cell pool, including progenitor cells of different levels of differentiation and different ability to proliferate. Accordingly, it can be expected that the subpopulation composit. We have studied of HSC subsets in 569 specimens of hemopoietic tissue (blood cells and LP cells) from 167 adult cancer patients and on 557 specimens of hemopoietic tissue from 263 pediatric cancer patients. Also, 61 samples of LP from 50 healthy HSC donors were studied. All patients were managed at bone marrow transplantation units of hematology malignancy and oncology department of N.N. Blokhin Cancer Research Center from 1996 to 2014. Peripheral hemopoietic stem cells (HSC) that are transplanted to cancer patients to reduce critical pancytopenia vary in subset composition and include early polypotent precursors (CD38- and/or HLA-DR-, CD90+, CD45-negative), lymphoid precursors (CD10+, CD7+, CD2+, CD19+, CD56+), megakaryocyte- (CD61+) and myeloid-committed precursors (CD117+, CD13+, CD33+). These subsets of early and committed HSC are found in different proportions in cancer patients and normal donors. So, the pool of mobilized HSC is heterogeneous and represented by pluripotent precursors and committed HSC in different proportions that are in variable, rather sophisticated interrelations. Mobilization effect of SC individual subsets is related with disease type. To achieve fast recovery of granulocyte lineages after HSC autologous or allogeneic transplantation one should not focus only on proportion of committed myeloid HSC: optimal HSC content to be transplanted should be in a certain balance.

Age Is Not Important for Autologous Peripheral Hematopoietic Stem Cell Transplantation in Multiple Myeloma

Introduction: High-dose melphalan followed by autologous hematopoietic cell transplantation (auto HSCT) has become the standard procedure for patients with symptomatic multiple myeloma (MM). Retrospective analyses suggest that the benefit of HDT extends to elderly myeloma patients, which is an important finding considering that the median age at diagnosis is 69 years (range: 65-74) for MM in United States, using 2010-2014 US SEER data. The aim of our study was to determine the effect of age on stem cell collection and engraftment in patients with MM.Materyal and Methods: From January 2010 through April 2016, data from 260 myeloma patients below the age of 65 were compared to 41 myeloma patients above 65 years of age who were eligible for auto HSCT according to geriatric assessment (GA), depending on the results of IMWG report in 2015. All these data were obtained from the Ankara University Faculty of Medicine Center for Therapeutic Apheresis and written informed consent was signed according to our institution regulations. Mostly bortezomib based regimens were given as induction therapy to our patients. Ninety two percent of the patients received only GCSF at a dose of 5 µg/kg BW twice-daily s.c. until stem cell procurement. Patients underwent further PBSC collections until we obtained the target dose >20 CD34+ cells/µL blood. A maximum of 3 collections were performed in the first mobilization; if the cell dose was not achieved, we submitted patients to a second mobilization.Results: Forty-one of 301 patients were above 65 years of age (median age 68, range 65-75) and 260 patients were below the age of 65 (median age 56, range 29-64). Baseline characteristics of the older and younger patient cohorts are summarized in Table-1. The median follow-up was 48.5 months (range 1-90) for age <65 years old patients and 46 months (range 1-90) for age ≥65 years old patients. Mobilization regimens for the younger patient population were G-CSF only (n:241), cyclophosphamide based (n:12) and +plerixafor (n:7). Mobilization in the older population was with cyclophosphamide based (n:4), G-CSF only (n:36) and +plerixafor (n=1) in whom poor mobilization had been predicted. The chemotherapy regimens were not statistically different between both age groups (chi square p value 0.37). There were no significant statistical differences in time from diagnosis to mobilization, number of prior therapies or disease status between both patient groups. The number of CD34-positive circulating cells before scheduled leukapheresis was mean 23.26 cells/μL in all patients (including patients who failed mobilization). Neutrophil engraftment was seen faster in elderly group (mean 10.4±3.1 vs. 11.5±1.8; p=0.008) but platelet engraftment was similar compared the younger patients with older ones (Table-2). In The probability of 5-year progression free survival (PFS) and overall survival (OS) in elderly patients with ISS-3 was 82.4%±12.1% and 48.5±16.5%. No statistical significance was observed for mean estimated 5-year OS in terms of patient age (<65 and ≥65 years; 82.5%±2.8% and 74.3%±8.7% p=0.29) (Figure-1). Less relapse was occurred in elderly cohort (17.5% vs. 35.4%) but the number of patients in this group does not provide enough statistical power to confirm whether the differences in PFS were statistically significant.Conclusion: To date, accepted approach for elderly patients with MM is not only improving survival, also their quality of life. Based on this single center study, auto-HSCT is safe and efficient in the treatment of elderly myeloma patients but no statistical difference was demonstrated in respect to age groups. [Display omitted] DisclosuresIlhan:Novartis: Consultancy.

Pilot Study of Safety and Efficacy of Chidamide in Allogenic Peripheral Hematopoietic Stem Cell Transplantation: Better Disease Control and Positively Lower Graft Versus Host Disease

IntroductionThe combination of busulfan (Bu) and fludarabine (Flu) is an effective and well-tolerated hematopoietic stem cell transplantation (HCT) conditioning regimen for patients with acute leukemia. However, relapse remains the main reason for treatment failure. Increasing intensity of conditioning therapy leads to not only better control of disease, but more treatment related mortality including graft versus host disease (GVHD). Song and Partow demonstrated that introducing histone deacetylase inhibitor (HDACi) vorinostat into busulfan/fludarabine/clofarabine (Bu/Flu/Clo) could augment disease control in vitro and in vivo, without increasing toxicity. Pavan and Choi showed vorinostat decrease GHVD while preserving graft versus leukmia effect. We conducted a clinical trial to evaluate the role of a selective HDACi chidamide in allogenic HCT.MethodsChidamide was given orally twice weekly at dose of 20 mg from day -7 to 2 weeks post transplantation. Busulfan was administered intravenously at fixed dose of 3.2 mg/kg for 4 days from day -6 to -3. Fludarabine and cytarabine were given intravenously at dose of 30 mg/m2 and 1g//m2 respectively for 5 days from day -6 to -2. GVHD prophylaxis was based on post-transplantation cyclophosphamide (50 mg/kg on day +3, +4) and cyclosporine started from day +5. The presence of minimal residual disease (MRD) was determined by multi-parameter flow cytometry.ResultsForty patients (24 AML, 6 MDS, 10 ALL) with median age 41 years (range 16-60) received an allogeneic matched sibling (n=34) or unrelated donor (n=6) HCT in CR1 (n=15), CR2 (n=6), with residual disease (n=10), or with active disease (n=9). Seventeen patients had adverse risk karyotype according to European LeukemiaNet risk stratification. Median time to ANC > 0.5 x 109/L and platelets > 20 x 109/L were 16 (range 9-36) and 18 days (11-44), respectively. Short-term (before recovery of ANC and platelets) adverse events included neutropenic fever (80%), reversible grade 2 elevation of liver enzyme (42.5%), and grade 2 mucositis (27.5%). Median follow-up time of the whole cohort was 11.5 months (3-24.7). All patients achieved CR and clearance of MRD by day +30 after HCT. All patients achieved 100% donor chimerism at 30 days following HCT. The incidence of grades II-IV and grade III-IV acute GVHD is 11% and 5% respectively. Only one patient died of aGVHD. Chronic extensive GVHD among 38 evaluable patients is 9%. Median follow-up time of the whole cohort is 11.5 month (3-24.7). Estimated progression free survival and overall survival at 1 year are 75% and 84.6% respectively (Figure1-A). Patients with MRD have inferior survival compere with patients without MRD (81.2% vs 68% p=0.336) (Figure 1-B).ConclusionShort-term results indicate introducing chidamide into allogeneic HCT could lead to better control of disease and possible lower GVHD. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Comparison of Outcomes of Post-Transplant Cyclophosphamide between Haplo-Identical and Matched/Mismatched Donor Peripheral Blood Stem Cell Transplantation

Introduction: Haplo-identical donor transplant (HIDT) with post-transplant cyclophosphamide (pCY) has emerged as a potential life-saving treatment modality for patients with limited donor availability. Although HIDT using bone marrow grafts with reduced intensity conditioning regimen has shown promising results, the data on peripheral stem cells are limited. In addition, very little is known about outcomes of cytokine release syndrome (CRS) in this population. We aimed to compare outcomes of pCY graft vs. host disease (GVHD) prophylaxis between HIDT (group 1) and mismatched unrelated, matched unrelated and related transplant (group 2) using peripheral hematopoietic stem cells transplants (PHSCT).Methods: We retrospectively reviewed consecutive adult patients with hematologic malignancies who underwent HIDT (group 1), mismatched unrelated, matched unrelated and related PHSCT (group 2). All patients received pCY as GVHD prophylaxis either alone or in combination with other agents. The primary objectives were to determine rate of GVHD, non-relapse mortality (NRM), relapse rate, relapse free survival (RFS) and overall survival (OS) in both groups at 1-year.Results: A total of 60 patients underwent peripheral blood stem cell transplant between January 2012 to October 2016. Forty patients received HIDT, whereas 10, 8 and 2 patients received mismatched unrelated, matched unrelated and related PHSCT, respectively. The median age of patients was 60.5 years (range, 19-73). AML was the most common diagnosis, followed by MDS and NHL. BU-FLU-TBI (53%) was the most common conditioning regimen used followed by BU-FLU (23%) and FLU-MEL-TBI (10%). The incidence of CRS was 89% in group 1. Grade 1, grade 2, grade 3 and grade 4 CRS was observed in 18 (50%), 9 (25%), 4 (11%) and 1 (3%) patients, respectively. Five patients required tocilizumab and 3 patients received systemic steroids for management of CRS. The median time to neutrophil engraftment was 18 days (range, 12-25) in group 1 and 17 days (range, 13-22) in group 2. The graft failure rate was 10% in each group.The 1-year cumulative incidence of grade III-IV acute GVHD was 7.7% (95% CI, 1.9-19%) in group 1 and 0% in group 2. The 1-year cumulative incidence of chronic GVHD was 21.1% (95% CI, 9.6-35.6%) in group 1 and 41.7% (95% CI, 17.3-64.7%) in group 2. The 1-year cumulative incidence of NRM was 25.2% (95% CI, 12.9-39.5%) in group 1 and 20.0% (95% CI, 6.0-39.9%) in group 2, whereas RFS was 51.5% (95% CI, 37.99-70.06%) in group 1 and 56.8% (95% CI, 37.57-86.11%) in group 2. The 1-year relapse rate was 23.4% (95% CI, 11.3-38%) for group 1 and 23.1% (95% CI, 6.2-46.2%). The median follow-up of living patients was 14.4 months (95% CI, 10.43-23.7) in group 1 and 16.5 months (95% CI, 8.69-NR) in group 2. The 1-year OS was 60.6% (95% CI, 46.76-78.75%) in group 1, and 65% (95% CI, 47.12-89.66%) in group 2. Slightly higher rate of CMV reactivation was observed in group 1 (55% vs 40%, p=0.412), whereas rates of EBV reactivation, C. difficile colitis, invasive fungal and bacterial infections were similar in both groups. No differences in NRM, RFS, relapse rate and OS were found between both groups in multivariable analyses. No differences in GVHD, NRM and OS were noticed in patients with CRS. Disease recurrence and infections were the most common causes of death.Conclusion: Our study demonstrates that pCY provides comparable rates of GVHD, relapse rate and OS in haplo-identical, mismatched unrelated, matched unrelated and related peripheral blood stem cell transplants. pCY can be used as GVHD prophylaxis to provide good post-transplant outcomes regardless of donor source. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

High-dose polychemotherapy with autologous hematopoietic stem cell transplantation in children with non-Hodgkin lymphomas

High-dose polychemotherapy with autologous hematopoietic stem cell transplantation in children with non-Hodgkin lymphomas

Successful autologous peripheral blood stem cell collection using large volume leukapheresis in patients with very low or undetectable peripheral blood CD34+ progenitor cells

Autologous stem cell transplantation provides some patients with hematolymphoid and solid organ malignancies an opportunity for cure. Management of peripheral hematopoietic stem cell (HSC) collections differs among institutions, especially if a very low pre-procedure peripheral blood CD34+ cell count (PBCD34) is demonstrated. This study retrospectively analyzed results of large-volume peripheral HSC collections in 91 patients over approximately two years. Fifteen patients with PBCD34 < 10 × 10e6/l (eleven with undetectable PBCD34) were compared to 76 patients with higher counts on the first collection day (adequate mobilizers). The poor mobilizer group had significantly lower pre-collection WBC and platelet counts as well as collection yields. However, most patients with PBCD34 < 10 × 10e6/l (80 %) collected the minimum target for HSC transplant (2.0 × 10e6 CD34+ cells/kg) in <5 consecutive days of collection, and those who did collect the minimum successfully underwent autologous transplantation, with hematopoietic engraftment and long-term survival comparable to the adequate mobilizers. Successful HSC collection may often be achieved regardless of d 1 PBCD34 counts.

Evans syndrome after Allogenic Peripheral Hematopoietic Stem Cell transplantation in a child with Severe Acquired Aplastic Anemia: case report and literature review

Evans syndrome after Allogenic Peripheral Hematopoietic Stem Cell transplantation in a child with Severe Acquired Aplastic Anemia: case report and literature review

Evaluation of the human type 3 adenoviral dodecahedron as a vector to target acute myeloid leukemia

Intensive systemic chemotherapy is the gold standard of acute myeloid leukemia (AML) treatment and is associated with considerable off-target toxicities. Safer and targeted delivery systems are thus urgently needed. In this study, we evaluated a virus-like particle derived from the human type 3 adenovirus, called the adenoviral dodecahedron (Dd) to target AML cells. The vectorization of leukemic cells was proved very effective at nanomolar concentrations in a time- and dose-dependent manner, without vector toxicity. The internalization involved clathrin-mediated energy-dependent endocytosis and strongly correlated with the expression of αVβ3 integrin. The treatment of healthy donor peripheral blood mononuclear cells showed a preferential targeting of monocytes compared to lymphocytes and granulocytes. Similarly, monocytes but also AML blasts were the best-vectorized populations in patients while acute lymphoid leukemia blasts were less efficiently targeted. Importantly, AML leukemic stem cells (LSCs) could be addressed. Finally, Dd reached peripheral monocytes and bone marrow hematopoietic stem and progenitor cells following intravenous injection in mice, without excessive spreading in other organs. These findings reveal Dd as a promising myeloid vector especially for therapeutic purposes in AML blasts, LSCs, and progenitor cells.

COPING WITH THE COVID19 PANDEMIC IN A HEMATOLOGY, TRANSPLANTATION AND CELL THERAPY UNIT IN SOUTHERN BRAZlL

We started 2020 with perspectives that quickly changed in March when the SARS-Cov-2 pandemic started in Brazil. Our center has a unit, called the Protected Environment with 30 beds with HEPA filters where malignant disease, autologous and allogeneic transplants are performed. In March 2020, the contingency plan designed since January to deal with COVID 19 pandemic of Porto Alegre Clinicas Hospital (HCPA) began highly restricting visits, consultations and elective procedures.&#x0D; Our challenge was to maintain the best care for our patients and healthcare professional’s safety. We suspend all visits and reduce relative patients’ companies to only essential. Our team was already one with the highest percentage of hand washing in the hospital, intensified infection control measures and implemented new individual protection equipment surgical masks and face shields. We started a new way to inform family members using digital platforms and improved the Wi-Fi network inside the unit to maintain patient external contact and reduce their loneliness. All Professional meetings and rounds became virtual.1,2,3&#x0D; When the first cases started in Porto Alegre, we had already implemented and validated the performance of the PCR for SARS-COV-2, with result until 24 hours. So, we could organize the flow of patients for hospitalizations avoiding admissions of Covid asymptomatic patients. HealthCare’s with any symptoms were kept away from work and quickly tested.&#x0D; We followed the guidance of the Brazilian society of BMT and started to perform only urgent transplants, greatly reducing the number of autologous transplants performed. All patients candidates stem cell transplant were instructed to maintain isolation for 14 days before admission and collected PCR 24 hours before admission. Related and unrelated bone marrow donors underwent clinical screening and PCR testing 24 hours before collection and the marrow was cryopreserved until results what changed our routine marrow infusion and sometime modified the collection from marrow to peripheral Hematopoietic stem cell in order to obtain adequate cellularity.1,2,3&#x0D; Despite all the difficulties and challenges the Covid pandemic imposed upon us, we managed to perform 16 Transplants from March to September, between autologous and allogeneic and we had no cases of covid transmission inside deaths related to COVID until now. All patients who had COVID19 or tested positive to SarsCov2 were outpatients, either from the Day Hospital or the outpatient clinic and had complete resolution of the condition.&#x0D;

Clinical Significance of Serum Immunoglobulin Level after Peri- pheral Blood Haploidentical Hematopoietic Stem Cell Transplantation in Patients with Hematologic Malignancies

To investigate the clinical significance of post-transplantation serum immunoglobulin level in the outcome of patients with hemalologic malignancies treated by haploidentical peripheral hematopoietic stem cell transplanta-tion(Haplo-HSCT). The clinical data of 157 patients treated by haplo-HSCT were analyzed retrospectively. The overall survival rate (OS), graft versus host disease (GVHD) incidence, infection incidence, serum immunoglobulin level, the relationship of immunoglobulin levels with OS and transplant complications were analyzed. The 2-year OS rate was 59.2%(95%CI:51.6%-66.9%), 2-year relapse mortality was 11.5%(95%CI: 6.4%-16.6%), and non-relapse mortality was 29.3%(95%CI:21.7%-36.9%). The cumulative incidence of III-IV aGVHD was 16.6%(95%CI:10.8%-22.9%); the cumulative incidence of extensive cGVHD was 21.7%(95%CI:15.3%-28.6%); the cumulative incidence of severe bacterial infection within 1 year was 59.2%(95%CI:51.6%-66.2%); the cumulative incidence of invasive fungal infection was 47.1%(95%CI:38.9%-54.8%). The occurrence of extensive cGVHD after haplo-HSCT related with the gender match of donor-recipient and bacterial infection. The levels of IgG in patients with 0-II aGVHD and patients with III-IV aGVHD for 1 month after haplo-HSCT were (6.96±2.47) and (4.27±2.42) g/L （P=0.003）, IgG levels at 3 months afte haplo-HSCT were (8.71±4.47) and (6.65±2.95) g/L (P=0.038); IgG levels at 1 month after haplo-HSCT showed predictive value for III-IV aGVHD susceptibility(P=0.003); for patients with IgG<4 g/L at any time after haplo-HSCT, the incidence of extensive cGVHD was significantly increased (35.5% vs 18.3%) (P=0.037), the incidence of fungal infection within 1 year after haplo-HSCT was significantly increased(71.0% vs 41.3%) (P=0.003), and the 2-year survival rate was reduced significantly (P=0.035). Haplo-HSCT is effective for the treatment of hematologic malignancies. Patients with lower IgG at 1 month after haplo-HSCT are more likely to develop III-IV aGVHD, and IgG levels at 1 month after haplo-HSCT can predict its susceptibility to a certain extent. Patients with severe hypoimmunoglobulinemia (IgG<4 g/L) after haplo-HSCT are more likely to develop extensive cGVHD, fungal infection and show worse survival prognosis.

Altered frequency of peripheral B‐cell subsets and their correlation with disease activity in patients with systemic lupus erythematosus: A comprehensive analysis

Alternations of peripheral B‐cell subsets are closely related to disease activity in systemic lupus erythematosus (SLE) and may also predict the relapse of SLE. In this study, we aimed to comprehensively analyse the frequency of peripheral B‐cell subsets, and their correlation with disease activity in patients with SLE. The results showed that for B‐cell subsets in the antigen‐independent differentiation stage, the frequency of the peripheral hematopoietic stem cell (HSC) subset in all patients with SLE was significantly higher than that of control patients. Surprisingly, several significant correlations were noted in newly diagnosed patients with SLE including a positive correlation in the frequency of the common lymphoid progenitor cell (CLP) with cholesterol serum levels. For B‐cell subsets in the antigen‐dependent differentiation stage, the frequency of naïve B‐cell (N‐B) subsets in all patients with SLE was significantly higher than that in the control patients. Moreover, the frequency of plasmablasts positively correlated with the SLEDAI score in the newly diagnosed patients. For memory B‐cell (M‐B) subtypes in the antigen‐dependent differentiation stage, the frequency of the class‐switched memory B‐cell (CSM‐B) subsets was positively correlated with the serum levels of complement C3. Notably, the frequency of the CSM‐B subset also negatively correlated with the SLEDAI score, whereas the non–class‐switched memory B‐cell (NSM‐B) subset was positively correlated with the serum levels of haemoglobin. Collectively, these findings may contribute to a better understanding of the role played by different B‐cell subsets in the pathogenesis of SLE.

Severe, Reversible Acute Lung Injury During Autologous Hematopoietic Stem Cell Mobilization After Filgrastim in a Child With Neuroblastoma: A Case Report

Peripheral blood hematopoietic stem cell mobilization is widely performed in a variety of clinical facilities and is believed to be a safe outpatient procedure. In this report, we describe a child with neuroblastoma who developed an extremely severe acute lung injury after granulocyte colony-stimulating factor was used for peripheral hematopoietic stem cell mobilization.A 3-year-old boy with a medical history of patent foramen ovale and secundum atrial septal defect was diagnosed with an MYCN-amplified neuroblastoma and treated with chemotherapy. During stem cell mobilization with filgrastim, the boy was in very good clinical condition, with a peripheral white blood cell (WBC) count of 57.17 K/μL, but he suddenly deteriorated, and nausea, seizures, and nystagmus were observed. The patient developed dyspnea with hemoptysis, and lung computed tomography showed bilateral asymmetrical pulmonary opacification demonstrating an anteroposterior density gradient. Because of rapidly progressing circulatory and respiratory failure, the child was hospitalized in the intensive care unit. Corticosteroid therapy, broad-spectrum antibiotic therapy, and cardiovascular support with mechanical ventilation were immediately instituted, and the child recovered without sequelae.The presented case emphasizes that life-threatening complications can occur during granulocyte colony-stimulating factor administration, and patient surveillance is warranted, especially if high leukocyte counts are observed or the patient exhibits cardiopulmonary signs.

Optimization of methods for collecting peripheral hematopoietic stem cells in children with cancer: literature review

Autologous hematopoietic stem cell transplantation (auto-HSCT) is a standard for the treatment of oncological, hematologic, and also some immune diseases, ensuring the restoration of blood counts after high-dose chemotherapy. In children, the success of mobilization and collection of hematopoietic stem cells (HSCs) is especially important. Mobilization schemes for children are decided on an individual basis, which requires the development and implementation of recommendations for improving the efficiency of mobilization and collection of HSCs. Mobilization schemes include the use of granulocyte colony-stimulating factor in the form of monotherapy or in combination with CXCR4 antagonists. These schemes are ineffective in some children, which requires re-mobilization or rejection of transplantation, which negatively affects the prognosis. When preparing a patient for HSCs collection, it is necessary to take into account all previous therapy, the patient’s age, weight and height indicators, and general somatic state. Harvesting the required amount of HSCs will allow for high-dose therapy followed by auto-HSCT, and thereby increase the effectiveness of treatment. It is necessary to optimize the protocol for mobilization of HSCs with a large bias for pediatric patients, which will clearly define the criteria for mobilization, give indications for this procedure and determine the criteria for technical collection, which will allow to obtain the optimal number of CD34+ cells, which will ensure the success of the treatment.

Outcome of peripheral blood allogeneic hematopoietic stem cell transplantation as a treatment option in patients with severe aplastic anemia between 40 and 50 years

The frontline treatment for patients younger than 40 years with severe aplastic anemia (AA) is allogeneic hematopoietic stem cell transplantation (HSCT) from a human leukocyte antigen-identical sibling donor. However, in patients with severe AA who are older than 40 years, allogeneic HSCT has been found to be associated with increased treatment-related mortality and toxicity, even when matched sibling donors are used. We report our institutional experience with allogeneic HSCT in patients with severe AA between 40 and 50 years. A total of 19 patients with severe AA were included in the study. Overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan–Meier method. The mean age of patients at the time of transplant was 43.79 years, and 57.9% were male. The mortality rate was 36.8%, attributed to infection (10.5%), relapse (15.8%), and renal failure (5.3%) in all cases. Acute graft-versus-host disease (GVHD) occurred in five patients (26.3%), and chronic GVHD occurred in two patients (10.5%). The 5-year OS was 62% and the 5-year DFS was 52%. We found that the patient's age, platelet level prior to transplantation, and the number of CD3 cells infused for each transplant were independent prognostic factors for OS, and the age and sex of the patient, graft rejection, and platelet level prior to transplantation were significant prognostic factors associated with DFS. We recommend that immunosuppressive therapy be considered as a first-line treatment in patients with severe AA who are older than 40 years. Allogeneic HSCT can be considered a valid alternative option in patients whose suppression therapy fails.

Clinical Analysis of Dasatinib and Chemotherapy Followed by Allogeneic Hematopoietic Stem Cell Transplantation for Treatment of Patients with Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia

To investigate the clinical efficacy, related side-effectt and long-term survival condition of Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ ALL) patients treated with second generation TKI dasatinib and chemotherapy followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT). Clinical data of 19 newly diagnosed as Ph+ ALL patients treated by dasatinib, chemotherapy and allo-HSCT from January 2012 to September 2018 were collectd and analyzed. There were 10 males and 9 females with median age of 29 years old. 14 patients were BCR/ABL P190 positive while 5 with BCR/ABL P210 positive. Three patients had complex karyotype, and 3 cases were confirmed to have central nervous system leukemia. All the patients received treatment with the induction chemotherapy regimen of VDCLP and consolidation regimens such as HD-MTX and MAE. 11 patients (57.9%) received dasatinib during induction chemotherapy, 3 patients (15.8%) received dasatinib after remission and 5 patients (26.3%) received dasatinib to replace imatinib. Side-effect appeared in 3 patients including rash, edema and nausea. All the patients got morphological remission and 7 patients(63.6%) got MMR after 4 weeks of induction chemotheraphy. 17 patients (89.5%) got MMR and 15 patients(78.9%) got CMR before allo-HSCT. All the patients received related bone marrow and peripheral hematopoietic stem cell transplantation from related donors, the median time of WBC and platelet engraftment were 12 d and 14 d after transplantation, respectively. The incidence rate of aGVHD and cGVHD were 42.1% and 57.9% respectivety. 13 patients received therapy of dasatinib after HSCT but 7 patients discontinued because of severe headache, vomiting and serious effusions. All the patients were followed-up for the median time of 42 months, the 3-year and 5-year OS both were 94.4%, and 3-year and 5-year RFS of 81.9% and 71.6%, respectively. First-line administration of dasatinib and chemotherapy followed by allo-HSCT for treatment of Ph+ALL is effective and patients can well-tolerate, the patients long-tern survival maybe superior to that of the patients treated with first generation TKI.

A Phase II Trial Evaluating the Efficacy and Safety of Sargramostim Post Infusion of T -Replete HLA Mismatched Peripheral Blood Haploidentical Hematopoietic Stem Cells with Post Transplant Cyclophosphamide

Phase II trial evaluating the Efficacy and Safety of Sargramostim Post Infusion of T -Replete HLA Mismatched Peripheral Blood Haploidentical Hematopoietic Stem Cells with Post-Transplant Cyclophosphamide Background: T-replete HLA mismatched haploidentical transplantation (Haplo) with post-transplant cyclophosphamide (PTCY) is widely used for patients lacking a suitably matched donor. Patients who receive haplo with PTCY usually start growth factor support (G-CSF) on day +5 for neutropenia prophylaxis. G-CSF is a specific stimulator of the growth and differentiation of hematopoietic progenitor cells committed to the neutrophil lineage. Granulocyte-macrophage colony-stimulating factor (GM-CSF) on the other hand, is not restricted to neutrophils because it also affects monocytes and eosinophils and plays a central role in antifungal host response. In a prior randomized study among 206 matched allogeneic HCT patients (wang et al, J Clin Oncol. 2015;33(34):3999-4006), neutropenia prophylaxis with GM-CSF +/- G-CSF had significantly lower 100-day TRM, lower 100-day cumulative mortality, lower infection related mortality and lower 600-day invasive fungal disease related mortality compared to G-CSF. Given the increase number of HLA mismatched haplos with PTCY performed each year and the high risk of infectious complications associated with this type of transplant, we suggest that GM-CSF administration post haplo and PTCY can yield similar count recovery rate to GCSF with a potential of lowering risk of infectious complications. Endpoints : The primary endpoint is to establish equivalent effectiveness of sargramostim to a matched control cohort of G-CSF treated patients in time to neutrophil engraftment (ANC&gt;500 x 3 days) post haplo with PTCY. Secondary endpoints: estimates of OS, DFS, relapse rate, GVHD and TRM. Donor chimerism at days 30, 60, 100 and 6 months post-transplant. Incidence and grade of cytokine release syndrome between day 0 and 30. Incidence of infectious complications and infection related mortality at day 100. Immune profiling assay "CYTOF" will be measured at days 30, 60, 90 and 180 for functional and phenotypic immune analysis. Other secondary endpoints include length of hospital stay and charges-based cost comparison during the first 100 days between sargramostim and G-CSF matched controls. All primary and secondary endpoints will be reported for the study group and compared to a matched control cohort from our database containing patients who received haplo with PTCY using G-CSF for neutropenia prophylaxis. A set of 20 patients, who are not on the Sargramostim study and receiving haplo transplant with G-CSF at the same time of the study accrual period, will be consented for immunoprofiling assay at days 30, 60, 100 and 180. Methods: Patients aged 18-78 years with an available 5/10-8/10 HLA- matched related donor with high risk hematological malignancy with adequate organ function will be enrolled for the study. Patients will receive Sargramostim 250mg/m2 /day subcutaneous starting day +5 post haplo/PTCY and continue till ANC&gt;1000x 3 days or &gt;1500x 1 day. If grade 3 or 4 adverse reactions occur, reduce dose by 50% or temporarily discontinue the dose until the reaction abates. Conditioning regimens to be used include previously published and currently used at our center (Flu/Cy/TBI, Flu/high dose TBI or Flu/Mel). Treatment will be in the outpatient setting and admissions if clinically indicated. Sample Size Determination : Time to ANC&gt;500 will be evaluated between the prospectively enrolled patients and matched historical controls. Based on the data of haplo transplants done at Northside in 2010-2016, the standard deviations (SD) was 3 days for time to ANC500. The correlation in measurements between prospective patient and matched control is conservatively assumed to be 0.1. SD for differences between matched pairs would be 3.55 days for time to ANC500. To control the type I error to be 5%, the 90% paired t confidence interval for difference in time to ANC500 should be constructed and its upper boundary will be compared to the non-inferiority margin 2 days. The size of 35 prospective patients provides the power 90% for concluding that time to ANC500 for Sargramostim is no more than 2 days longer than historical controls. The actual enrollment size is decided to be 38 to accommodate 10% of drop off rate. Enrollment: The study is expect to start enrolling patients October 2019. Disclosures No relevant conflicts of interest to declare.

Veno-Occlusive Disease (VOD) after Hematopoietic Stem Cell Transplant (HSCR): Always a Catastrophic Illness?

Introduction Veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS), a potential life-threatening complication of conditioning regimens performed for HSCT, is due to an endothelial cell activation/damage and a prothrombotic-hyper-fibrinolytic condition. The clinical diagnosis and grading of VOD/SOS are based on the Seattle, Baltimore and EBMT criteria. Aims The aim of our work was to establish the incidence of VOD/SOS in our patient series, the time of clinical diagnosis, the best treatment options in relation to disease severity, the effectiveness of defibrotide treatment for severe/very severe forms, and the incidence of multi-organ failure (MOF). Methods Patients In the period January 2016-June 2019, 146 allogeneic HSCT were performed at our Institution. Patients' median age was 57 years (range 25-72) and 52% of them were males. The primary disease was AML in 82 (56.1%), MDS in 33 (22.6%), ALL in 16 (10.9%), MM in 5 (3.4%), primary or secondary Myelofibrosis in 10 (6.8%). Performance status was good (Karnofsky score ≥90) in 80% of HSCT. At HSCT, 31 patients (21.2%) had either had a previous hepatic disease or increased levels of alanine transaminases (ALT) and 36 (24.6%) had altered pulmonary functional tests. Thirty-five HSCTs were from HLA identical siblings, 55 from MUD and 35 from haplo-identical family donors. Conditioning regimen were either myeloablative or RIC depending on patients' age and co-morbidities. Stem cell source was BM in 36 (24.6%) patients, peripheral hematopoietic stem cells in 109 (74.6%) and cord blood in one. Standard acute GVHD prophyaxis consisted of Cylosporine A (CsA) and short methotrexate or CsA and micofenolate mofetyl in haplo-transplants. Definition, grading and treatment of VOD Diagnosis and grading of VOD/SOS were based on the Seattle, Baltimore and EBMT criteria. Renal dysfunction was defined as serum creatinine ≥3x baseline value, creatinine clearance or glomerular filtration rate declined to ≤40% of baseline or dialysis dependence due to VOD/SOS. Pulmonary dysfunction was defined as oxygen saturation ≤90% on room air, requirement for supplemental oxygen to maintain oxygen saturation ≥90%, or ventilator dependence not due to infection. Abdomen echo-tomography was performed in all patients to evaluate the presence of ascites. Patients having a pre-transplant liver disease or increased ALT levels received ursodeoxycholic acid (UDCA) as pharmacological prophylaxis Results In our series VOD/SOS occurred in 22/146 patients (15.0%) according to Seattle criteriaand in 13 (8.9%) according to Baltimore criteriaand the recent EBMT scale. Median time to VOD/SOS development was 7 days post-HSCT (range 0-18). Based on the proposed EBMT scale for grading, 9 patients were classified as mild VOD/SOS, one as moderate, 11 as severe and one as very severe. VOD/SOS target organs were the liver in 6 patients, the liver and the lung in 6 and the lung in one. Defibrotide treatment (6.25/kg/day for 21 days) was promptly started in 12 patients including the case with the moderate form of VOD/SOS and delayed by 23 days in one patient. VOD/SOS progression occurred in 7 patients: one evolved from a mild to a severe form and 6 from a severe to a very severe form. Defibrotide treatment induced a response in 10 patients: 8 achieved a complete response and 2 a partial response. However, these last two patients died of a thrombotic microangiopathy syndrome three and four months post-transplant. The remaining 3 patients, including the case with a delayed defibrotide start, experienced a multi-organ failure (MOF) that had been preceded by a liver (one case) and a lung VOD/SOS (two cases). Interestingly, the patient with a liver VOD/SOS had showed a severe liver dysfunction on pre-transplant work-up and the remaining two with a lung VOD/SOS a severe lung dysfunction on pre-transplant work-up. Conclusions In our series the incidence of VOD/SOS is similar to that reported by the literature; two organs involvement predicts a high risk of MOF evolution; UDCA is the therapy of choice for mild VOD/SOS; defibrotide, especially if promptly started, is very effective in inducing VOD/SOS resolution. Disclosures No relevant conflicts of interest to declare.

A Comparison of the Effect of Granulocyte-Colony Stimulating Factor (G-CSF) in Chemotherapy Versus Plerixafor for Hematopoietic Stem Sell Transplantation (HSCT) and Mobilization

INTRODUCTION: Peripheral Hematopoietic Stem Cells have been widely used as a source for Autologous Hematopoietic Stem Cell Transplantation (HSCT). The use of G-CSF associated with chemotherapy increases the number of circulating Hematopoietic Progenitor Cells; however, there is no harmony about the best medical strategy for the use of G-CSF associated with the mobilization conduct. The use of plerixafor for poorly mobilized patients has provided a safe and effective option for optimizing apheresis procedures despite the high cost. Thus, the evaluation of efficacy becomes essential for the incorporation of plerixafor into the HSCT routine. OBJECTIVE: To evaluate the mobilization of autologous HSCT in chemotherapy associated with G-CSF and cyclophosphamide (QT) versus plerixafor. METHODS: Retrospective evaluation of 66 patients mobilized for autologous HSCT with G-CSF associated with chemotherapy versus plerixafor (plerixafor was used in the first mobilization), also to evaluate the number of apheresis procedures, CD34-positive cells, cell viability and for the bone marrow engraftment date. Statistical analyses were performed with GraphPad Prism 5.0 (GraphPad Software, Inc., San Diego, CA), using the Mann-Whitney test for nonparametric data (p &lt;0.05). RESULTS: A mobilization protocol was performed in 83 patients (60% male), with a median age of 55 years (17 to 68 years). Multiple myeloma (55.7%), Hodgkin's lymphoma (14.7%), Non-Hodgkin's lymphoma (16.39%), primary amyloidosis (4.9%) were the most common hematologic malignancies. There was no statistical difference between G-CSF and QT group versus plerixafor groups regarding age, sex, type of disease and previous QT. The plerixafor group had better CD34 positive cell counts compared to G-CSF and QT (median 6.2 versus 3.8 x106, p&lt;0.004), shorter sessions of apheresis procedure (median 2 versus 4, p &lt; 0.0002) and a better cell viability rate (98 versus 95%, p &lt;0.0034). The bone marrow engraftment rate was 10 days for plerixafor group versus 15.05 days for G-CSF and QT group, p &lt;0.0055 (Figure 1).CONCLUSION: Our results showed the mobilization group using plerixafor had superior data and statistical significance regarding the number of apheresis procedures, cell viability, number of CD34 positive stem cells and earlier bone marrow engraftment rates when compared to the G-CSF + QT. These findings suggest and encourage the use of plerixafor in the first mobilization, as well as it should be incorporated into the standard routine. In addition, the number of apheresis procedures will be reduced, cell viability and CD34-positive cells rate will be increased. As a result, there will be a better medullary recovery and the reducing of both hospital costs and infectious complication rates. Disclosures No relevant conflicts of interest to declare.

Human Interleukin 15 (IL15) Humanized NCG Mice Support the Human Natural Killer Cells Reconstitution and Development

NCG (GPT strain ID: T001475), one of the highly immune-deficient mouse models generated so far, is ideal for engraftment of human tissues and cells, such as patient derived tumors (PDX), human cancer cell lines (CDX), human peripheral blood mononuclear cells (PBMC) and human hematopoietic stem cells (HSCs). NK cells that are a critical component of the innate immune system have diverse biological functions, such as recognizing and killing viral-infected and neoplastic cells. Human HSCs (CD34+) could reconstitute human T but not NK cells in NCG mice. The cytokine Interleukin 15 (IL-15) plays a critical role in the generation of NK cells from HSCs. IL-15 is produced by non-lymphoid cells, including monocytes, dendritic and bone marrow stromal cells. Human and mouse IL-15 are only 70% identical to each other in primary amino acid sequence. Mouse IL-15 poorly supports the reconstitution of human NK cells. To overcome this problem, several lines of transgenic mice that express human IL-15 (hIL-15) have been established. However, the non-physiological levels of hIL-15 expression are detrimental to human immune system reconstitution.In the current study, we developed hIL-15 knock-in in NCG mice (NCG-hIL-15), in which the mouse IL-15 (mIL-15) gene was replaced by the hIL-15 gene. We quantified the mRNA expression of hIL-15 and found that the levels of hIL-15 expression in the BM, liver, lung, and small intestine of NCG-hIL-15 mice were similar to those of mIL-15 in NCG mice.Based on these data, we expect that NCG-hIL-15 mice can efficiently support the development, maturation and function of human NK cells. In the future, we will further study human NK cell engraftment and human NK cell-mediated cancer immunotherapy in NCG-hIL-15 mice. Taken together, our newly developed NCG-hIL-15 mice offer a novel mouse model for studying human NK cell biology and human NK-mediated cancer immunotherapy in vivo. Disclosures Ju: GemPharmatech Co., Ltd: Employment. Zhang:GemPharmatech Co., Ltd: Employment. Wu:GemPharmatech Co., Ltd: Employment. Tang:GemPharmatech Co., Ltd: Employment. Li:GemPharmatech Co., Ltd: Employment. Zhao:GemPharmatech Co., Ltd: Employment. Wang:GemPharmatech Co., Ltd: Employment. Gao:GemPharmatech Co., Ltd: Employment.

Safe and Efficient Peripheral Blood Stem Cell Collection in Patients with Sickle Cell Disease Using Plerixafor

Background: Hematopoietic stem cell (HSC) gene therapy is potentially curative for sickle cell disease (SCD) provided that a sufficient quantity of long-term engrafting CD34+ HSCs can be safely collected and infused. In patients with SCD, peripheral blood (PB) mobilization with granulocyte colony stimulating factor is contraindicated, and steady-state bone marrow (BM) harvesting is associated with suboptimal HSC quality and yield. Hence, agents that promote safe and effective peripheral HSC mobilization in SCD are required. Methods: This phase I multicenter study investigated the safety and efficacy of plerixafor mobilization (240 µg/kg) followed by apheresis, processing, and HSC enrichment in 15 adult subjects with SCD (NCT03226691). Hydroxyurea treatment was stopped at least two weeks prior to mobilization and all participants who were not receiving long-term transfusion therapy received prophylactic red blood cell exchange prior to plerixafor administration to achieve a target sickle Hb (HbS) &lt;30%. The primary endpoint was efficient collection of PB HSCs (target 2.0x106 CD34+ cells/kg, minimum 1.5x106) after plerixafor mobilization without serious adverse events (SAEs). Collection products were assessed for total WBC, CD34+, CD3+, and CD19+ composition by flow cytometry. Spearman's correlation test was used to assess the relationship between baseline CD34/µL, total CD34+ cells/kg collected, and total blood volume processed. Findings: Fifteen participants with SCD (HbSS n=13, HbSC n=1, HbSβ+ n=1) who met inclusion criteria were enrolled at St. Jude Research Children's Hospital (n=3) or NIH (n=12) between July 2017 and February 2019. All participants except one successfully met the minimum target CD34+ cells/kg yield with 2 or fewer mobilization and apheresis procedures, with almost half the participants (n=7) achieving ≥5.0x106 CD34+ cells/kg. The total WBC count increased by an average of 3.2-fold over baseline (range 1.7-5.0) to an average peak WBC count of 26.5x103/µL (range 14.1-47.4), with counts returning to baseline within 1-2 days. Median total WBC, CD34+, CD19+, and CD3+ cells/kg in the final apheresis product after one (n=12) or two (n=3) collection procedures were 0.9 x109 WBC/kg (range 0.4-1.7), 4.5x106 CD34+ cells/kg (range 0.9-12.0), 3.4x108 CD19+ cells/kg (range 0.5-4.9), and 3.6x108 CD3+ cells/kg (range 1.7-7.3), respectively. There was a strong positive correlation between baseline CD34/µL and total CD34+ cells/kg (rs = 0.7776, 95% CI 0.446-0.9215, p = 0.001). Participants with the lowest pre-apheresis CD34 cell count generally underwent higher blood volume processing (rs = - 0.1443, 95% CI -0.6075 to 0.3921, p = 0.59) in an effort to achieve target yields. However, higher blood volume processing did not translate to higher total CD34+ cells/kg collection yields (rs = - 0.2104, 95% CI -0.6488 to 0.3328, p = 0.43). A median of 97% of positively selected CD34+ cells were CD34high (range 73.6-99.4%) compared to 1.3% CD34low (range 0.09-24.4%) phenotype suggesting enrichment for long-term engrafting HSCs. Seven grade III AEs (two non-pain and five pain related) and one grade IV AE (non-pain - hemolysis) occurred and each resolved with symptomatic treatment. Plerixafor mobilization was overall safe and in most cases generated CD34+ cell yields that were sufficient for both genetic modification and back-up allogeneic transplantation (median cell yield 4.2x106 CD34+ cells/kg). Interpretation: This first multi-institutional phase I study suggests the efficiency and safety of plerixafor mobilization and apheresis collection in 15 adult subjects with SCD. The primary endpoint to obtain a target of 2.0x106 CD34+ cells/kg from the PB was exceeded without SAEs. Importantly, immunophenotyping data suggest that for individuals with SCD, the plerixafor mobilized cell product is more enriched for long-term engrafting HSCs compared to CD34+ cells isolated from BM. Given the risks of general anesthesia and the low quality and yield of CD34+ cells harvested from the BM of individuals with SCD, plerixafor mobilization represents a safe and potentially superior alternative for HSC isolation. Disclosures Hankins: Novartis: Research Funding; ASPHO: Honoraria; NHLBI: Research Funding; LYNKS Foundation: Research Funding; NHLBI: Honoraria; National Committee for Quality Assurance: Consultancy; Global Blood Therapeutics: Research Funding; Bluebird Bio: Consultancy. Sharma:Vertex Pharmaceuticals: Other: Study PI; Doris Duke Foundation: Research Funding. Weiss:GlaxoSmithKline: Consultancy; Rubius INC: Consultancy; Esperian: Consultancy; Beam Therapeutics: Consultancy; Cellarity INC: Consultancy.